(57) A method of increasing the molecular weight of a poly(aryl ether) comprising providing
a mixture of (1) at least one polyaryl ether comprising polymer chains having end
groups selected from groups of formula
and
and 2) a reagent having nucleophilic activity selected from a) alkaline salts of Group
I or Group II metals (as hereinafter defined) and b) reagents have radicals -X and
-OZ, reactive respectively with the end groups-Ar-OZ and-Ar-X, wherein when the end
group is -Ar-X the reagent is either a difunctional reagent having either both end
groups in the form of reactive -OZ groups or a difunctional reagent having one reactive-OZ
group and one reactive-X group and when the end group is -Ar-OZ the reagent is a difunctional
reagent having reactive end groups -X, and wherein Ar represents an arylene radical,
preferably a phenylene radical, X is a monovalent radical capable of nucleophilic
displacement from Ar, preferably selected from halogen, nitrile (CN) or nitro (NO2) radicals, Y is an electron withdrawing group, which when Ar is phenylene is positioned
ortho or para, preferably para to the X group and when Ar is not phenylene, X and
Y are attached to the Ar group by parallel and oppositely directed bonds and Z is
a univalent metal, and heating the mixture to a temperature above the melting point
of the polymer until a desired increase in molecular weight has occurred. The method
is useful for preparing fibre reinforced compositions and particularly for the process
of impregnating fibre structures.
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